number of core register in Cortex-M4

Question

so, I am a little bit confused right now while reading Cortex M4 technical reference Manual , I came to this line in section 3.8 page 46:

Processor core register summary

The processor has 32-registers that includes 13 general-purpose registers and several special-purpose registers.

but When I counted them they were about 16 register not 32 according to Cortex M4 technical reference Manual.

on the other hand, while reading the Cortex M4 generic user guide , I come to this table where it shows around 23 register as in the photo

, please note that PSR register is in fact 3 register not one as I understood from the user guide, so where are the rest of the registers?, as according to technical reference manual, it's supposed that there are 32 core registers.

Answer 1

This looks like a typo. The manual talks about "32- bit registers", not "32 registers".

The processor has the following 32-bit registers:

• 13 general-purpose registers, r0-r12
• Stack Pointer (SP) alias of banked registers, SP_process and SP_main
• Link Register (LR), r14
• Program Counter (PC), r15
• Special-purpose Program Status Registers, (xPSR).

See https://developer.arm.com/documentation/ddi0439/b/Programmers-Model/Processor-core-register-summary